You have all probably customised the Quick Access Toolbar (QAT), but I find many people have failed to notice they can assign buttons to specific documents so the button only appear in the QAT when that document I open. This works in all Office applications except Outlook and OneNote.
Firstly open the document, worksheet etc. to which you want to attached specific QAT buttons.
Customise the Quick access Toolbar as normal but before you add any specific buttons make sure that you select the document in the top-right drop-down selector rather than using the default All Documents option.
Complete the customisation process adding any buttons as required.
Finally, close your document and make sure that you save the changes as the button are saved with the document.